Five people were arrested at the time of the incident, which began when officers spotted a woman they thought was drinking on the beach. But police announced two more arrests Saturday following more witness interviews and examination of evidence.
The fight ensued when the group the woman was with turned on the officers after being confronted, according to Huntington Beach police.
All seven people arrested are in their late teens and early 20s, and are facing multiple charges of participating in a riot and resisting officers, as well as consuming alcohol on the beach.
One officer was transported to a hospital with injuries described as serious, and will require further treatment.
A number of other officers sustained minor injuries, police said.
Police say the group involved in the incident and the altercation had no connection to the U.S. Open of Surfing.